Padding stl strings in C++

Question

I\'m using std::string and need to left pad them to a given width. What is the recommended way to do this in C++?

Sample input:

123
         


        

Answer 1

std::string pad_right(std::string const& str, size_t s)
{
    if ( str.size() < s )
        return str + std::string(s-str.size(), ' ');
    else
        return str;
}

std::string pad_left(std::string const& str, size_t s)
{
    if ( str.size() < s )
        return std::string(s-str.size(), ' ') + str;
    else
        return str;
}